1. Field of the Invention
The present invention relates to a liquid crystal display apparatus in which an electrode terminal group of liquid crystal display elements (hereinafter referred to as LCD) are connected to a printed circuit board through flexible substrates.
2. Description of the Prior Art
FIG. 3 is a partial plan view showing an example Of a conventional liquid crystal display apparatus.
In the figure, an LCD which is shown collectively by a symbol 1 comprises an upper glass substrate 2, a lower glass substrate 3, liquid crystal being sealed between the glass substrates 2 and 3, a polarizing plate, not shown in a drawing, etc. On the opposing surfaces of the substrates 2 and 3, transparent electrode group 4's are patterned, and from each transparent electrode 4, a terminal 5 is protrusively formed toward a connecting edge portion (a terminal portion) of the LCD 1. The transparent electrode group 4's and the electrode terminal group 5's are composed of ITO and the like, and they are formed in a unity.
A flexible substrate collectively shown by a symbol 6 comprises a base film 7 composed of a polyimide film, etc., a plurality of lead patterns 8's formed by etching a copper film on the base film 7, and a cover film, not shown in a drawing, covering the lead patterns 8's, and on both edge portions of the base film 7, the lead pattern group 8's are exposed. Electronic parts 9 such as an LSI are mounted on the flexible substrate 6.
After an anisotropic conductive sheet, not shown in a drawing, is stuck on the connecting edge portion of the LCD 1 where the electrode terminal group 5's are exposed, a plurality of flexible substrates 6, 6,--are placed in parallel on the edge portion in a state where the electrode terminal group 5's and the lead pattern group 8's are aligned, and the corresponding electrode terminal 5 and the lead pattern 8 are connected and fixed through the above-mentioned anisotropic conductive sheet by pressing and heating each flexible substrate 6 using a heater tip, etc.
A circuit pattern for driving the LCD 1 is formed on the printed circuit board denoted collectively by a symbol 10, and a connecting terminal group 11's of the circuit pattern are connected and fixed to the lead pattern group 8's of the flexible substrate 6 through the anisotropic conductive sheet similar to the above-mentioned connecting constitution.
The printed circuit board 10 is fixed inside a box, not shown in a drawing, by caulking, and a display area of the LCD 1 can be observed through a display window of the box.
In a conventional liquid display apparatus of this kind, a grounding pattern is provided on the printed circuit board 10, and the grounding pattern is connected to the caulking portion of the box as a measure against the disturbances caused by static electricity or noise in the printed circuit board 10, but the LCD itself is not grounded, so that there may occur an erroneous operation (erroneous display) in the LCD I influenced by static electricity or noise.
There is no lead pattern 8 between the adjacent flexible substrates 6 and 6 in the connecting edge portion of the LCD 1, and, as shown in FIG. 3, the electrode terminal group 5's to be connected to a flexible substrate 6 are extended from the transparent electrode group 4's toward the edge portion forming a space between them which gets narrower toward the edge portion; thereby, an area A which gets wider toward the edge portion having no terminals in it occurs between an electrode terminal 5a to be connected to one of the flexible substrates 6 and 6 which are disposed adjacently and another electrode terminal 5b to be connected to another one of the flexible substrates 6 and 6. The area A having no terminal in it is an area where a cell gap is larger than the other area by the thickness of the electrode terminal 5; thereby, there can be a defect that color shades are apt to occur in the peripheral part of the display area of the LCD 1.
The present invention is invented considering the above-mentioned circumstances, and an object of the invention is to offer a liquid crystal display apparatus which is not easily influenced by static electricity or noise and also color shades are not easily generated in the peripheral part of the display area of the LCD 1.